This invention is best described with reference to spot-weld removal operations. The task of removing spot-weld interconnections between two flat members is typically time-consuming and difficult. Spot-weld removing operations are regularly and frequently practiced in a variety of situations, most notably in vehicle panel replacement in auto body shops.
In repairing and refinishing collision damaged sheet metal parts of automotive vehicles, such as the body panels and fenders thereof, it is often necessary to remove a damaged outside panel from the vehicle in order to straighten or otherwise recondition the same. When the sheet metal panels are joined together by spot-weld, the damaged outside panel is typically separated from the undamaged outside panel either by drilling a hole of sufficient diameter through both panels so that the entire spot-weld portion of the panels are removed, or by splitting the spot-welded seam apart by driving a thin sharp chisel between the two panels.
However, in removing spot-weld interconnections, it is usually highly desirable to remove the metal of the damaged outside panel at the location of a spot-weld interconnection without removing any of the metal below the interface of the damaged and undamaged panels. Invasion of metal coincident with the undamaged inside panel is undesirable. Removal of the metal from the damaged outside panel is sufficient to disconnect the panels, provided the metal removal is at the weld location.
Extremely careful tool manipulation and use is necessary to achieve removal of the outside panel member without invading the undamaged inside panel. It is this which makes the operation difficult and time-consuming.
Among other things, it is often difficult to control the depth of tool movement into the interconnected flat panels. The inside undamaged panel is usually invaded unless extreme care is taken in the operation. The operator is often required to guess the thickness (gauge) of the damaged panel, and even then is unable to properly limit the metal removal.
Specialized tools have been developed to aid in the removal of spot-weld portions in sheet metal work. Among these, is a tool disclosed by Hougen U.S. Pat. No. 3,104,564 teaching a complicated article for separation of spot-weld panels. Another expensive, complicated and unreliable spot-weld removing tool is disclosed by Perrone U.S. Pat. No. 4,735,528.